A foam duct has been proposed that is produced by blow molding in which a resin is foamed at a high expansion ratio and is formed into a desired shape (see Patent Document 1).
The foam duct has connection openings at both ends that are configured to fit in other components of a vehicle air conditioner and a duct body between the connection openings that defines a three-dimensionally winding conduit as an air passage. The connection openings and the duct body are made of foam cells having an average foam particle size of from 100 μm to 300 μm, which are produced by blow molding from a single-layer parison foamed by physical foaming.